I travel quite a lot and always put sellotape around all tubes and bottles at the join where they are likely to leak, then wrap in plastic and put in my main suitcase, because you dont need them on your journey,and have never had a spill, also take sellotape with me for the return journey, except in the US where I can buy cheaper on arrival at any Walgreens or Walmarts. yes you can take in your luggage more than 100ml, but not in hand luggage.
Good luck with BA to me they are one of the worst airlines ever and did you know that on arrival in Zambia you have to pay something like a wopping $ 150 on entry and departure, but if you are going on a mission, they will pay it for you.Have a safe journey and if you meet an english guy called Harry pls give him my love, he is my son and I miss him.